Officials can’t predict reopening date for SF’s...

1of2A closer up of one side of the Salesforce Transit Center Fremont Street overpass where two beams were found cracked on Wednesday, Sept. 26, 2018, in San Francisco, Calif. The weight bearing beams's lower horizontal flanges are cracked the full width (2.5') of the 4" thick steel beams, manufactured in the Central Valley, Calif. They are both cracked at the same mid point on each side of the bridge according to Dennis Turchon, Senior Construction Manager. That will be the right and left side of the photograph.Photo: Paul Kuroda / Special to The Chronicle

2of2Transbay Transit Center workers unload hydraulic jacks that will be used to temporarily support the damaged building while cracked beams are inspected.Photo: Michael Cabanatuan / The Chronicle

Transbay Transit Center officials said Thursday they’re working as quickly as they can to get the building’s cracked support beams repaired but still don’t have a date for resuming bus service or reopening the popular rooftop park.

Mark Zabaneh, executive director of the Transbay Joint Powers Authority, which built and operates the $2.2 billion transit hub and is overseeing its repair, told the agency’s board Thursday that he understood frustration over the lack of information.

“Unfortunately, we do not have a timeline for reopening the center now,” he said.

Officials have announced that Fremont Street, which runs beneath the transit center at the location of the cracked beams, will reopen Wednesday. It was originally set to reopen Friday.

The date was delayed because the process of shoring up the cracked girders turned out to be more complex than anticipated. Crews are bolstering the beams with large steel columns in the middle of Fremont Street. Traffic will be routed around those structures when Fremont reopens.

Once the failed beams have been shored up, engineers can start testing the metal on them, determine why they cracked and design repairs. The lab results should be available the first week of November.

Some tests, including magnetic, ultrasonic and chemical examinations, have already been done, said Dennis Turchon, senior construction manager. But the metallurgical tests that involve cutting pieces of metal from the beams — it’s called “destructive testing” — are key to deciphering what went wrong.

Meanwhile, Zabaneh said, engineers are working on three to four prospective repair options, trying to get a head start depending on the test results.

The discovery of cracks in the two critical support girders on Sept. 25 prompted officials to shut down the $2.2 billion transit hub and its rooftop park just six weeks after they opened. Beams above First Street, which are not cracked, have also been bolstered as a precaution.

On Thursday, board members seemed more concerned about making sure the tests and repairs are done correctly.

Ed Reiskin, the San Francisco Municipal Transportation Agency’s transportation director, asked whether First Street is being adequately braced. Tilly Chang, executive director of the San Francisco County Transportation Authority, wanted to know if other parts of the center are being monitored for damage and the impacts of the temporary bracing.

“We don’t know yet where this is going to take us,” said Jeff Gee, a board member and director of the Peninsula Corridor Joint Powers Board. “While there is a sense of urgency to this, we have to make sure we have the right fix, and make sure it is safe for everyone.”

Zabaneh assured board members the authority is proceeding with caution while trying to act quickly.

The Transbay shutdown has been a headache for bus riders and drivers, but it hasn’t yet slowed interest in leasing retail space in the center, said Martha Velez, the authority’s facility manager.

“The deals in the pipeline do not reflect a slowdown in interest or activity,” she said.

Some retail spaces are taking longer to fill, she said, because they’re mostly operated by small local retailers, which move more slowly than national brands. Tenants who have signed leases are being allowed access to the terminal to build out their spaces, even as it remains closed to commuters, Zabaneh said.

Velez said multiple tenants are interested in the retail spaces that are still available, including the rooftop restaurant space.

Michael Cabanatuan has covered all things transportation for the San Francisco Chronicle — from BART strikes, acrobatic bridge construction and dark dirty tunnel excavations to the surging ridership on public transportation and the increasing conflict as cars, bikes and pedestrians struggle to coexist on the streets. He’s ridden high-speed trains in Japan, walked in BART’s Transbay Tube and driven to King City at 55 mph to test fuel efficiency.

He joined The Chronicle as a suburban reporter and deputy bureau chief in Contra Costa County, and has also covered the general assignment beat. In addition to transportation, Michael covers a variety of Bay Area news, including breaking news events. He’s been tear-gassed covering demonstrations in Oakland and exposed to nude protesters in the Castro District. Michael is also a regular contributor to the City Insider column and blog.